The present invention relates to the use of fatty acid derivatives of the general formula I:
A1xe2x80x94COxe2x80x94R1xe2x80x83xe2x80x83I
as surfactants for cleaner systems for cleaning grease-soiled nontextile material, where the substituents have the following meanings:
A1 an aliphatic C8-C24 radical with unbranched carbon chain, which contains in the chain one or more groups of the formula II: 
R1 an xe2x80x94N(R2)R3 radical, a hydroxyl radical and its alkali metal or ammonium salts, a C1-C4-alkoxy radical or a radical of a mono-, di- or triglyceride, it being possible for the two latter to be radicals of natural saturated or unsaturated fatty acids or identical or different radicals A1;
R2 a hydrophilic radical having 2-40 carbon atoms;
R3 hydrogen, a C1-C4-alkyl radical or one of the R2 radicals.
The invention additionally relates to the novel fatty acids of the formula Ia;
A1xe2x80x94COOR4xe2x80x83xe2x80x83Ia
where R4 is hydrogen or an alkali metal or ammonium cation of the corresponding fatty acid salt, and A1 has the meaning stated at the outset, and to their use as surfactants. The invention further relates to surfactant formulations comprising compounds I or Ia. DE-A 27 34 596 discloses fatty acid derivatives of type I as detersive substances for washing textiles.
For cleaning nontextile surfaces, surfactants must have additional properties such as good fat-removal capacities. Cleaning processes of this type take place mainly in the metal industry, in the food industry, in the catering trade and in the household. Thus, for example, it is often necessary to remove drawing and rolling greases from metal articles after processing thereof. The primary object in the other sectors mentioned is also in particular to remove fats of varying origin from equipment and containers, because fats prevent the wetting of other soiled particles.
It is an object of the invention to use surfactants for aqueous cleaner systems for cleaning nontextile material with an improved fat-removal capacity.
We have found that this object is achieved by using the amino hydroxy fatty acid derivatives I defined at the outset for cleaning nontextile grease-soiled materials, the compounds Ia as novel substances, and formulations containing I.
Compounds I can be obtained in a manner known per se by epoxidizing fatty acid esters III: 
and further reaction of the epoxidized products IV with an amine V: 
with opening of the epoxide ring. A2 in this case is an unsaturated radical which corresponds to the saturated or partially saturated radical A1 in I, and B1 is the radical of a 1- to 3-hydric aliphatic C1-C6-alcohol. In the case of a polyhydric alcohol, its other hydroxyl groups may also be esterified, preferably with fatty acids.
Depending on the chosen ratio of III to V there is mainly reaction of the epoxide groups with the amine V. If there is an excess of amine, B1 is replaced by the radical xe2x80x94N(R2)R3.
The esters obtained where appropriate in the reaction can be used, for example, to prepare the novel fatty acids or their alkali metal salts by known reactions such as alkaline hydrolysis and, if required, acidification.
The ammonium salts, which are likewise novel, can be obtained preferably directly from the epoxidized fatty acids by reaction with V. This results in the preferred ammonium salts with ⊕NH2R2R3 as cation, where R2 and R3 have the same meanings as in the amino group of the fatty acid ester. Any desired ammonium salts can be prepared by subsequent reaction of a fatty acid Iaxe2x80x2 with an amine.
Among unsaturated unbranched aliphatic fatty acids from which the esters III are derived, the unsaturated hydroxy fatty acid ricinoleic acid is suitable, but preference is given to:
monounsaturated C9-C25-fatty acids such as petroselinic acid, undecenoic acid, xcex949-decylenic acid, xcex949-dodecylenic acid, vaccenic acid, palmitoleic acid, erucic acid and, in particular, oleic acid
diunsaturated C9-C25-fatty acids such as stillingic acid, preferably linoleic acid
triunsaturated fatty acids such as eleostearic and, preferably, linolenic acid.
Unsaturated C18-fatty acids are particularly suitable because they are readily available. The acids obtainable by isomerization of the double bond are also suitable.
It is likewise possible to use mixtures of fatty acids or fatty acid esters like those obtainable, for example, by transesterification or hydrolysis of natural fats with C1-C4-alcohols.
The preparation of compounds I preferably starts from natural fats, ie. the glycerol esters comprising at least one unsaturated radical A2. Examples of such natural fats are olive oil, cotton-seed oil, linseed oil, tallow, fish oils, tall oils, castor oil, coconut oil, dodder oil, sunflower oil, peanut oil, palm oil, euphorbia oil and, in particular, soybean oil and rapeseed oil.
The epoxidation is carried out in a manner known per se by reacting compound III with peracids such as performic acid and peracetic acid. However, some epoxidized fatty acid esters IV are also commercially available.
The amines V are primary or secondary amines having at least one hydrophilic aliphatic C2-C40 radical. The amines may be branched and have several hydroxyl or amino groups, such as tris(hydroxyethyl)methylamine, but preferably have at least one unbranched (xcfx89-hydroxyalkyl radical or an xcfx89-aminoalkyl radical having 2 to 6 carbon atoms, it being possible for the alkyl radical to be interrupted by nonadjacent oxygen atoms, xe2x80x94NH groups, Nxe2x80x94C1-C4-alkyl groups or Nxe2x80x94C1-C4-hydroxyalkyl groups. Also suitable are Nxe2x80x94C1-C4-alkyl-substituted derivatives if they also contain at least one reactive amino or imino group. Suitable and preferred in this connection are:
hydroxyalkylamines such as mono- and diethanolamine, mono- and diisopropanolamine, 2-(2-aminoethoxy)ethanol, 2-(2-aminoethylamino)ethanol, 3-aminopropanol and N-alkyl-substituted hydroxyalkylamines such as methylethanolamine, n-propylethanolamine, butylethanolamine, 2-amino-1-butanol and, particularly preferably, aminopropyldiethanolamine.
aminoalkylamines such as ethylenediamine, trimethylenediamine, 1,2-propylenediamine, 3-amino-1-methylaminopropane, diethylenetriamine, dipropylenetriamine, N,Nxe2x80x2-bis(3-aminopropyl)ethylenediamine, 3-(2-aminoethoxy)propylamine, 2-(2-aminoethoxy)ethylamine, 3-(3-aminopropoxy)propylamine and their symmetrically and asymmetrically N-substituted mono- and dialkyl derivates such as N,N-dimethylaminopropylamine, diethylaminoethylamine, diethylaminopropylamine, 1-diethylamino-4-aminopentane, neopentanediamine, hexamethylenediamine, 4,9-dioxadodecane-1,12-diamine, 4,7,10-trioxatridecane-1,13-diamine, 3-(2-aminoethyl)-aminopropylamine.
Amines which are likewise preferred and result in products with beneficial properties are polyalkylene glycol amines of the general formula VI:
R4xe2x80x94(Oxe2x80x94CnH2n)yxe2x80x94(Oxe2x80x94C2H4)xxe2x80x94(Oxe2x80x94CnH2n)zxe2x80x94NH2xe2x80x83xe2x80x83VI
where
n is 2, 3 or 4
x is from 1 to 10
y and z are from 0 to 10
R4 is hydrogen or a C1-C4-alkyl radical,
having a total of 3 to 40, in particular 3 to 20 carbon atoms. These known amines are normally obtained by alkoxylating aliphatic C1-C4-alcohols or ethylene glycol and subsequently aminating. This alkoxylation can take place either with ethylene oxide, propylene oxide and/or butylene oxide or mixtures thereof.
Examples of suitable amines are methylglycolamine and methyltetraglycolamine.
The reaction of the epoxidized fatty acid esters, acids or their salts with the amines normally takes place at from 30 to 170xc2x0 C., preferably in the presence of an alkaline catalyst such as alkali metal hydroxides, carbonates or alcoholates, for example sodium methoxide. The reaction is complete when epoxy groups are no longer detectable. The reaction is complete after about 2 to 4 hours at 100xc2x0 C.
The reaction can be carried out in the presence of a solvent, but this is usually unnecessary, so that a solvent is preferably omitted.
The amine is generally employed in an amount which is from stoichiometric to 10 molar, preferably stoichiometric to 2.5 molar, relative to epoxy units. If epoxidized fatty acids are reacted, it is advisable to react with at least 2 equivalents of amine because part of the amine reacts to form the ammonium salt.
Stoichiometric reaction of the fatty acid esters with the amines results particularly in fatty acid esters as products, whereas reaction with 1.4 to 10 equivalents of the amine results predominantly in the fatty amides. A larger excess of amine is possible but in some circumstances means that it is subsequently necessary to remove the unreacted amine. Both the esters and the amides have, as nonionic surfactants, an excellent fat-dissolving capacity, while the fatty acid amides are somewhat more soluble in water. In addition, the acids and salts show a very good fat-dissolving capacity while being very soluble in water so that they are very suitable as anionic surfactants.
Reaction of the epoxidized compound IV with the amines V usually results in mixtures of isomers because the oxirane rings may open at both Cxe2x80x94O bonds.
Reaction starting from natural fats results in a mixture which may contain not only compounds I but also glycerol and possibly the amides of saturated fatty acids. However, it is unnecessary to remove these substances for the use according to the invention because they do not interfere.
The amino hydroxy fatty acid derivatives I show, in use tests, good fat-dissolving properties as are required for surfactants in aqueous cleaning systems for nontextile surfaces. The surfactants I additionally show good foam-reduction behavior. The cleaning processes described at the outset are mainly carried out mechanically, for which the use of foam-reducing surfactants is important. Since vigorous circulation of water takes place in mechanical cleaning, otherwise a large amount of foam will be produced, which will weaken the mechanical cleaning power. Because of this exceptionally good foam-reduction behavior, the surfactants I are also suitable for use in compositions such as rinse aids for dishwashing machines, in which case the fat-removal capacity tends to be of low importance.
Besides the cleaning of kitchenware, the surfactants are also suitable for cleaning all nontextile surfaces which occur domestically and commercially, such as metal, painted wood, plastic or ceramic products, for example china, floor and wall tiles. The compositions can be applied for this purpose, for example, manually with a damp cloth or sponge or else by spray cleaning.
The compositions are normally marketed in the form of aqueous concentrates and can be used diluted or undiluted. Examples of conventional cleaners for nontextile surfaces are windshield cleaners, car shampoos, oven cleaners, window/imitation leather cleaners, plastics cleaners, toilet cleaners, scouring agents and bath cleaners.
The fatty acid derivatives I according to the invention are thus particularly suitable for aqueous cleaning systems for grease-soiled nontextile surfaces because, besides the good fat-removal capacity, they also effectively reduce foam. In this connection, it is particularly the nonionic surfactants, especially from the group of fatty amides, which are preferred for the use according to the invention. In addition, they can be obtained easily and have good biodegradability.
The water-based cleaner systems for cleaning nontextile materials comprise according to the invention surfactants I, their mixtures and, where appropriate, builders, solvents or solubilizers and other additives conventional for compositions of these types in the amounts conventional for the compositions. It is possible in this connection to use the surfactants I in combination with anionic or nonionic surfactants as mentioned, for example, in DE-A 27 34 597.
Very suitable rinse aids for dishwashing machines comprise, for example, 10 to 40, preferably 15 to 30%, by weight of I
5 to 30% by weight of a solubilizer such as alcohol or cumenesulfonate and
1 to 20% by weight of other conventional additives such as acids, for example citric acid or dicarboxylic acids.
A manual dishwashing composition consists, for example, of 5 to 50, preferably 5 to 30%, by weight of I
5 to 30% by weight of a solubilizer such as cumenesulfonate or alcohol and
0.5 to 5% by weight of skin-protecting agents, fragrances and dyes.
A composition according to the invention for a dip-degreasing composition for metal articles consists, for example, of 1 to 10, preferably 1 to 5%, by weight of I and 10 to 70% by weight of alkaline builders.